Sign holder



FIG. 1 is a top plan view of a sign holder showing my new design;

FIG. 2 is a bottom plan view;

FIG. 3 is a front elevational view, the rear elevational view being a mirror image thereof;

FIG. 4 is a side elevational view, the opposite side being a mirror image thereof; and,

FIG. 5 is a perspective view thereof, with the broken line showing for illustrative purposes only and forming no part of the claimed design. 

The ornamental design for a sign holder, as shown and described. 